Those are the questions rocking the tech and publishing worlds after Amazon.com pulled all of Macmillan's titles, digital and physical, off its virtual shelves late last week.

That move was the opening salvo in a war between Amazon and Apple over the future of ebooks.

Amazon's boycott came one day after Macmillan CEO John Sargent flew to its Seattle headquarters to ask for flexible pricing on books sold through Amazon's Kindle e-reader -- and just a few days after Apple announced that its upcoming iPad tablet would feature an ebook store.

Currently, Amazon.com sets the top price on most Kindle titles at $9.99. Macmillan hoped to raise prices to $14.99 -- the price point Apple announced for the iPad's iBookstore.

The talks did not go well. Sargent left Seattle empty-handed -- and then blogs like VentureBeat began noticing that Macmillan's books were gone from Amazon. (Amazon.com still offers Macmillan titles sold by third parties.) He announced the dispute in an open letter to authors and retailers.

On Sunday, Amazon announced that it was "capitulating" to Macmillan's higher prices.

The issue isn't really the price point, though publishers would obviously like to charge as much as they can. The real issue is who sets the price. Currently, Amazon essentially acts as a publisher for Kindle ebooks, licensing the copyright from book authors and publishers and paying them a cut.

Macmillan and others would like to sell directly to online consumers, setting the price and paying the operator of an ebook store a smaller percentage of sales. That's the business model Apple is offering.

If Amazon is the only one who can set prices, or if it can run its store in such a way that high-priced ebooks are disadvantaged, what's stopping them from raising prices later? Or dropping them to the point that book publishing becomes unprofitable?